In a semiconductor memory, for example, a flash memory, miniaturization of a device is advanced for reducing a manufacturing cost, and the number of devices for one chip is increasing.
In association with the miniaturization of the device, a failure, which has not been problematic so far, might be exposed. For example, considering a leak current of a field effect transistor resulting from the miniaturization, although the leak current of one device is minute, the leak current of an entire chip is large. Such leak current might cause an increase in power consumption of the memory and deterioration in reliability of memory operation.
Further, the failure of one device in a certain circuit might lead to the failure of an entire circuit.